PHP：如何获取无密钥URL参数

Question

I would like to get the parameter in a key such as http://link.com/?parameter

I read somewhere that the key is NULL and the value would be parameter.

I tried $_GET[NULL] but it didn't seem to work.

Here is my code:

if ($_GET[NULL] == "parameter") {
    echo 'Invoked parameter.';
} else {
    echo '..';
}

It just prints out .. so that means I'm not doing it right. Can someone please show me the right way.

Answer 1

There are no such things as keyless URL parameters in PHP. ?parameter is the equivalent of $_GET['parameter'] being set to an empty string.

Try doing var_dump($_GET) with a url like http://link.com/?parameter and see what you get.

It should look something like this:

array (size=1) 'parameter' => string '' (length=0)

Thus, you can test it in a couple of ways depending on your application needs:

if (isset($_GET['parameter'])) {
   // do something
} else {
   // do something else
}

or

// Only recommended if you're 100% sure that 'parameter' will always be in the URL.
// Otherwise this will throw an undefined index error. isset() is a more reliable test.

if ($_GET['parameter'] === '') {
   // do something
} else {
   // do something else
}